Circuit Description
The manifold absolute pressure (MAP) sensor responds to changes in the intake manifold pressure, or vacuum. The MAP sensor signal voltage to the PCM varies from below 2 volts at idle, when the vacuum is high, to above 4 volts with the ignition ON and the engine OFF, or at wide-open throttle (WOT), when the vaccum is low.
The MAP sensor is used to determine manifold pressure changes while the linear EGR flow test diagnostic is being run, to determine barometric pressure (BARO), and to determine engine vacuum level for some other diagnostics. Refer to DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient . The PCM monitors the MAP signal for voltages outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is intermittently high, DTC P1106 will set.
Conditions for Running the DTC
| • | There are no throttle position (TP) sensor DTCs present. |
| • | The ignition is ON. |
| • | The throttle angle is steady below 2 percent, if the engine speed is less than 900 RPM. |
Conditions for Setting the DTC
| • | The MAP sensor intermittently indicates a voltage of more than 4.2 volts. |
| • | The above conditions are present more than 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM doesl not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM stores the conditions that were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the MIL/DTC
| • | A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Check for the following conditions:
| • | The map sensor-- Monitor the MAP sensor using the scan tool. If the MAP sensor does not respond to throttle changes, check the 3X circuits from the ignition control module to the PCM. |
| If the 3X signal is lost the PCM will only update the MAP sensor reading once per key cycle, when the engine is first started. |
| Depending on whether the MAP sensor voltage is high or low when the engine is started, a high or a low voltage MAP sensor DTC will set. |
| • | Faulty connections--Inspect PCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Use a corresponding mating terminal to test for correct terminal tension. |
| • | A damaged harness-- Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP display on the scan tool while moving the related connectors and wiring harnesses. A change in the display will indicate the location of the fault. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important:: If DTC P1635 5 Volt Reference Circuit is set, perform that diagnostic first. Is DTC P0108 also set? | -- | Go to DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage | |
3 | Is DTC P1111, P1115, and/or P1121 also set? | -- | ||
4 | Inspect the ground circuit of the MAP sensor for a poor connection at the harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
5 | Inspect the ground circuit of the PCM for a poor connection at the harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
6 | Test the signal circuit of the MAP sensor for an intermittent short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 | Test the 5 volt reference A circuit of the MAP for an intermittent short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 | Test the ground circuit for an intermittent open. Did you find and correct the condition? | -- | Go to Diagnostic Aids | |
9 |
Does the DTC reset? | -- | System OK |
